Delicate dry clean

Abstract

A method of selectively removing fluorocarbon layers from overlying low-k dielectric material is described. These protective plasma treatments (PPT) are delicate alternatives to traditional post-etch treatments (PET). The method includes sequential exposure to (1) a local plasma formed from a silicon-fluorine precursor followed by (2) an exposure to plasma effluents formed in a remote plasma from a fluorine-containing precursor. The remote plasma etch (2) has been found to be highly selective of the residual material following the local plasma silicon-fluorine exposure. The sequential process (1)-(2) avoids exposing the low-k dielectric material to oxygen which would undesirably increase its dielectric constant.

Description

CROSS-REFERENCES TO RELATED APPLICATIONS[0001]This application claims the benefit of U.S. Prov. Pat. App. No. 61 / 823,995 filed May 16, 2013, and titled “DELICATE DRY CLEAN” by Zhu et al., which is hereby incorporated herein in its entirety by reference for all purposes.STATEMENT AS TO RIGHTS TO INVENTIONS MADE UNDER FEDERALLY SPONSORED RESEARCH AND DEVELOPMENT[0002]Not ApplicableREFERENCE TO A “SEQUENCE LISTING,” A TABLE, OR A COMPUTER PROGRAM LISTING APPENDIX SUBMITTED ON A COMPACT DISK[0003]Not ApplicableBACKGROUND OF THE INVENTION[0004]Integrated circuit fabrication methods have reached a point where many hundreds of millions of transistors are routinely formed on a single chip. Each new generation of fabrication techniques and equipment are allowing commercial scale fabrication of ever smaller and faster transistors, but also increase the difficulty to make even smaller, faster circuit elements. The shrinking dimensions of circuit elements, now well below the 50 nm threshold, ha...

AI Technical Summary

Benefits of technology

The patent describes a way to remove protective layers of fluorocarbon material from overlying low-k dielectric material without damaging the underlying material. The method involves two sequential exposures to different plasmas, one containing silicon-fluorine and another containing fluorine-containing precursors. The second exposure is highly selective towards the residual material after the first exposure. This method helps to maintain the low-k dielectric material's integrity and prevents it from being exposed to oxygen, which can increase its dielectric constant.

Problems solved by technology

These protective plasma treatments (PPT) are delicate alternatives to traditional post-etch treatments (PET).

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